This invention relates to the analysis of particles and, more particularly, to a composition for manipulating the optical and electrical properties of particles for subsequent analysis by selected measuring devices and a method for using the composition.
It has become axiomatic in the field of medical science that the diagnosis and treatment of disease and illness must be predicated on a precise analysis of the patient's biological systems. The respiratory, circulatory, immune and nervous systems contribute to the overall well-being of a person and, if any one of these systems is compromised by a foreign organism, such as a virus or bacterial agent, serious health consequences may result. One way of ascertaining the health of a system is to evaluate its constituent biological particles, such as its red blood cells, white blood cells, antibodies and platelets. The information revealed by the examination of these constituent biological particles is invaluable to the physician or lab technician in assessing the status of the overall system and, thus, determining the cause of illness or disease.
The analysis of biological particles requires a detailed examination of the individual properties of the particles. Even slight deviations in the values of certain properties are sufficient to allow the diagnosis and treatment of disease and illness at very early stages of progression. It is therefore critical to obtain the highest degree of accuracy and reliability in the measurements of those properties so that an effective course of treatment can be planned.
The technology for analysis of biological particles has advanced dramatically over recent years. Direct current electronic particle counters are among these advancements. These instruments determine the size and volume of biological particles by measuring the electrical resistance of the particle relative to its surrounding fluid. Some electronic particle analyzers utilize radio frequency to measure the composition and nature of the material within the particle. In addition, optical methods of particle analysis, such as nephelometry and flow cytometry, employ either an incandescent or a laser light source for measuring light scatter and light absorption of the particle. These and other optical analysis techniques have evolved to yield qualitative and quantitative information on the size of the particle, its surface composition, its constituent elements and, in some applications, the concentration of its internal components, such as hemoglobin in red blood cells. Optical flow cytometry is capable of even more sophisticated cell analysis, including the use of immunological techniques for tagging unique cell structures and soluble cellular entities. Virtually all of these instruments are based on precise measurements of the electrical and optical properties of the biological particle.
Several challenges have confronted those seeking to take advantage of the many opportunities presented by these particle analyzer instruments. First, concomitant with the advent of these technologies, there has arisen a corresponding need for quality control. One of the first control products for monitoring the accuracy of particle analyzers utilized fresh whole human blood. Unfortunately, fresh human blood posed several disadvantages when used as a control: First, it was necessary that the particles within the blood be counted to establish a base reference value. This necessitated visual determinations by a technician using microscopy. Second, fresh blood was usable as a control for only a limited time, generally less than one day. Each day required the acquisition of a new fresh blood control which, in turn, meant daily reference counting. In addition, it was not possible to compare results between laboratories due to the limited shelf life of the material and inherent variances in control samples.
Preserved non-fresh blood controls were developed to overcome the disadvantages of fresh blood. Non-fresh blood controls have been derived from plastics and, more prevalently, adapted from both human and non-human blood cells. The non-human components of blood control products typically utilize blood cells from selected animals which closely approximate the size and other features of the particle to be assayed, such as human leukocyte subpopulations. Because biological particles, in general, and leukocyte subpopulations, in particular, vary significantly in size, these non-human cell control products must utilize cells from several different animals to create analogs for the individual subpopulations. The size of the analogs must account for changes in the native leukocyte as the result of chemical insult, such as treatment by detergents or hypotonicity, which remove non-leukocyte particles from the sample and prepare the leukocyte analog for specific unique particle analysis procedures. As can be readily appreciated, this results in a complex composition utilizing various animal cells, each requiring particularized treatment to create a control product for the desired biological particle which, in turn, must be treated for the specific instrument to be utilized.
Medical science notwithstanding, there are also numerous industrial endeavors requiring precise particle analysis. There is a growing use of particle analysis in industry for the manufacture of non-medical products such as cosmetics, textiles and the like. Existing instruments for analyzing these products similarly examine the electronic and optical features of the product's constituent particles. These applications also require quality control to ensure the manufacture of the highest quality goods achievable. There is a corresponding deficiency in these industrial arts for a suitable method for designing custom particles for use as control products for these applications.